Abstract: A shelf for protecting the inner surface of a vertical shell of a pulverizer against wear. It is partially replaceable. The shell accommodates a screw shaft and is filled with a pulverizing medium and a material to be pulverized. At least one of them is magnetizable. The shelf is made up of vertical and circumferential ribs and mounted in the shell. It is divided both vertically and circumferentially into a plurality of blocks that are coupled together by bolts and nuts. Magnets are provided in the spaces defined by the ribs. By turning the screw shaft, the pulverizing medium is pushed radially outward and partially trapped in the above spaces, thus forming a wear protective lining. When any of the ribs is worn, only the block that includes this rib is replaced with a new one.

Abstract: A pulverizer has a shell having an inlet port for introducing air and the material to be pulverized into the shell and a discharge port through which the pulverized product is discharged from the shell. The shell is filled with a pulverizing medium such as steel balls. A vertical screw shaft having a screw blade thereon is rotatably mounted in the shell. The screw shaft is hollow and provided at the bottom end thereof with an outlet port. The outlet port is located behind the screw blade with respect to the direction of rotation of the screw shaft. A fluid supply box is provided at the bottom of the screw shaft and extends from the screw shaft to the outer edge of the screw blade. The outlet port is formed in the fluid supply box. A scrape plate protrudes downwards from the bottom end of the screw shaft. Three or more screw blades may be provided.